/*
 * Copyright (C) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.sentry;

import java.util.Queue;

/**
 * Decorates another {@link Queue} to synchronize its behaviour for a multi-threaded environment.
 *
 * <p>Methods are synchronized, then forwarded to the decorated queue. Iterators must be separately
 * synchronized around the loop.
 *
 * @param <E> the type of the elements in the collection
 * @since 2021-06-02
 */
final class SynchronizedQueue<E> extends SynchronizedCollection<E> implements Queue<E> {
    /**
     * Serialization version
     */
    private static final long serialVersionUID = 1L;

    /**
     * Constructor that wraps (not copies).
     *
     * @param queue the queue to decorate, must not be null
     * @throws NullPointerException if queue is null
     */
    private SynchronizedQueue(final Queue<E> queue) {
        super(queue);
    }

    /**
     * Constructor that wraps (not copies).
     *
     * @param queue the queue to decorate, must not be null
     * @param lock the lock to use, must not be null
     * @throws NullPointerException if queue or lock is null
     */
    @SuppressWarnings("ProtectedMembersInFinalClass")
    protected SynchronizedQueue(final Queue<E> queue, final Object lock) {
        super(queue, lock);
    }

    /**
     * Factory method to create a synchronized queue.
     *
     * @param <E> the type of the elements in the queue
     * @param queue the queue to decorate, must not be null
     * @return a new synchronized Queue
     * @throws NullPointerException if queue is null
     */
    static <E> SynchronizedQueue<E> synchronizedQueue(final Queue<E> queue) {
        return new SynchronizedQueue<>(queue);
    }

    // -----------------------------------------------------------------------

    /**
     * Gets the queue being decorated.
     *
     * @return the decorated queue
     */
    @Override
    protected Queue<E> decorated() {
        return (Queue<E>) super.decorated();
    }

    @Override
    public E element() {
        synchronized (lock) {
            return decorated().element();
        }
    }

    @SuppressWarnings("UndefinedEquals")
    @Override
    public boolean equals(final Object object) {
        if (object == this) {
            return true;
        }
        synchronized (lock) {
            return decorated().equals(object);
        }
    }

    // -----------------------------------------------------------------------

    @Override
    public int hashCode() {
        synchronized (lock) {
            return decorated().hashCode();
        }
    }

    @Override
    public boolean offer(final E elements) {
        synchronized (lock) {
            return decorated().offer(elements);
        }
    }

    @Override
    public E peek() {
        synchronized (lock) {
            return decorated().peek();
        }
    }

    @Override
    public E poll() {
        synchronized (lock) {
            return decorated().poll();
        }
    }

    @Override
    public E remove() {
        synchronized (lock) {
            return decorated().remove();
        }
    }
}
